#define LEDPIN_RED 23
#define LEDPIN_GREEN 2
#define LEDPIN_YELLOW 18
#define BUTTON_PIN 33

int currentState = 0; // 0: Green, 1: Yellow, 2: Red
unsigned long greenStartTime = 0;
unsigned long greenDuration = 3000; 

void setup()
{
  pinMode(LEDPIN_RED, OUTPUT);
  pinMode(LEDPIN_GREEN, OUTPUT);
  pinMode(LEDPIN_YELLOW, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
}

void loop()
{
  // Green state
  if (currentState == 0){
    greenStartTime = millis(); // time when Green started

    // run green for 3000 OR until button gets pressed
    digitalWrite(LEDPIN_GREEN, HIGH);

    while (millis() - greenStartTime < greenDuration && digitalRead(BUTTON_PIN) == HIGH){
      delay(50);
    }

    digitalWrite(LEDPIN_GREEN, LOW);

    currentState = 1;// change state to Yellow
  }
  
  // Yellow state
  else if (currentState == 1){
    digitalWrite(LEDPIN_YELLOW, HIGH);
    delay(500);
    digitalWrite(LEDPIN_YELLOW, LOW);
    currentState = 2; // Change state to Red
  }
  
  // Red state
  else{
    digitalWrite(LEDPIN_RED, HIGH);
    delay(1500); // Red time duration
    digitalWrite(LEDPIN_RED, LOW);
    currentState = 0; // Change state to Green
  }
}